> For the complete documentation index, see [llms.txt](https://docs.abi.am/abi-omicss-guide-2021/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.abi.am/abi-omicss-guide-2021/week-2/r-programming/functions.md).

# Functions

Functions play a critical role in any R program and you tend to write a lot of them while programming. This section focuses on functions in R.

## Functions in R

To start, watch the following videos outlining the concept of functions in R:

1. [Your First R Function](https://www.coursera.org/learn/r-programming/lecture/BM3dR/your-first-r-function)
2. [Functions (part 1)](https://www.coursera.org/learn/r-programming/lecture/LP1kF/functions-part-1)
3. [Functions (part 2)](https://www.coursera.org/learn/r-programming/lecture/2xbdl/functions-part-2)

## swirl Exercises

Complete **swirl Lesson 9: Functions**, to solidify what you just learned, and return here afterward.

## Congratulations!

If you made it here, then congratulations! You have successfully completed this section. Move to the next portion of the guide with the arrow buttons below.


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